Surface covering incorporating a locking joint

ABSTRACT

Surface coverings comprising individual covering elements, such as for decking are known. However, known constructions have problems including separation of the joints between planks as the material of the covering elements contracts over time. Existing products make use of harmful solvent based adhesives for securing the elements together, the application of which is also labour intensive. A surface covering comprising two or more covering elements, each covering element having a first part comprising a female member; a second part comprising a male member for engagement with a female member, the first part having a top surface and a basal surface, the basal surface extending beyond the top surface to provide an open recess for reception of the male member, the second part having a top surface and a basal surface and a male member protruding therebetween, the female member and the male member providing an interference fit upon engagement.

The present invention relates to a locking joint for joining elements ofa surface covering. The invention has particular, but not exclusive,application for flexible surface coverings. Such flexible surfacecoverings may, for example, be used for synthetic decking. Otherapplications of the present invention will be readily apparent to thoseskilled in the art in view of the advantages described herein.

Synthetic decking, especially for marine applications, already exists.There are however many problems with the present products. Some of theseproblems include separation of the joints between planks as the materialcontracts over time which is a characteristic of the plastics used. Mostof the existing products make use of harmful solvent based adhesives forthe joints, the application of which is also labour intensive. Theseproducts can produce a burning sensation on bare skin making themimpossible to stand or lie on in hot climates especially as they becomesmooth surfaced, they become less anti-slip and can even cause anaquaplaning effect in very wetted conditions. The flexible nature ofthese decking materials and their design do not lend themselves to flateven application and an uneven finish results especially noticeable whenwet. These products are also hard and have little or no cushioning tofalls or knocks.

According to a first aspect of the present invention a surface coveringcomprises two or more covering elements, each covering element having

a first part comprising a female member;

a second part comprising a male member for engagement with a femalemember,

the first part having a top surface and a basal surface, the basalsurface extending beyond the top surface to provide an open recess forreception of the male member,

the second part having a top surface and a basal surface and a malemember protruding therebetween, the female member and the male memberproviding an interference fit upon engagement.

Preferably the open recess extends between the top surface and the basalsurface beneath the top surface to receive the male member beneath thetop surface.

Preferably the top surface terminates adjacent the open recess in aninclined surface.

More preferably the first part is further provided with an abutment andthe second part is provided with a recess, the abutment beingaccommodated within the recess upon engagement.

Still more preferably one of the abutment and recess is provided with aprotrusion, the other of the abutment and recess is provided with agroove, the protrusion being received within the groove upon engagement.

Preferably upon engagement of the male and female part a channel isformed in an upper part of the covering between the male and femaleparts

More preferably a sealing element is located in the channel. Preferably,upon engagement the sealing element is under compression.

Preferably the sealing element is formed as a co-extrusion with thefemale or male part of each covering element.

Preferably the sealing element is located on the male part above themale member. More preferably the sealing element is located in thechannel subsequent to engagement.

Preferably the upper surface of at least one covering element isprovided with one or more of a roughened surface, channels or grooves.

Preferably the lower surface of at least one covering element isprovided with one or more of a roughened surface, channels or grooves.

Preferably each covering element is provided with ducts or channelsextending along a length of the covering element.

Preferably at least one covering element is provided with at least onephotovoltaic cell. More preferably, the at least one photovoltaic cellis retained in an upper surface of the covering element, or in which thephotovoltaic cell is retained beneath a transparent or substantiallytransparent part of the covering element.

Preferably at least one covering element is provided with at least onelighting element.

Preferably at least one covering element is provided with one or moremagnetic elements.

Preferably at least one covering element is provided with one or morestiffening elements.

Preferably the basal surface is provided with apertures extendingtherethrough.

According to a second aspect of the invention a joint comprises

a first part comprising a female member;

a second part comprising a male member for engagement with a femalemember,

the first part having a top surface and a basal surface, the basalsurface extending beyond the top surface to provide an open recess forreception of the male member,

the second part having a top surface and a basal surface and a malemember protruding therebetween, the female member and the male memberproviding an interference fit upon engagement.

According to a third aspect of the invention a floor covering isprovided comprising forming a covering surface according to the firstaspect of the invention and securing the covering surface to the floor.

Preferably the covering elements are joined to one another by sliding.

Optionally a lubricant may be provided to aid such sliding.

According to a further aspect of the invention a covering element isprovided incorporating one or more from a number of photovoltaic cells(or strips), a lighting element, a magnetic element and a stiffeningelement.

The invention will now be described, by way of example only, withreference to the accompanying drawings, in which:

FIG. 1 a is a sectional view of male and female joints of a lockingjoint in a surface covering in accordance with the present invention;

FIG. 1 b is an illustration as to how covering elements having suchjoints may be slid together;

FIG. 1 c shows a section of surface covering deformed to cover anon-linear path;

FIG. 2 shows in side section a further embodiment of the invention;

FIG. 3 a shows in side section the joints of FIG. 2 in an assembledcondition;

FIG. 3 b shows in side section the joints of FIG. 2 during assembly;

FIG. 4 shows a sectional view of a further embodiment of a coveringelement for use in the present invention.

FIG. 5 shows a sectional view of a further joint formed by coveringelements in accordance with the invention;

FIG. 6 show a sectional view of another joint formed by coveringelements in accordance with the invention;

FIG. 7 shows a perspective view of further adjacent covering sectionsforming a surface covering in accordance with the present invention;

FIGS. 8 a, 8 b and 8 c illustrate further features of the coveringelements.

FIG. 9 shows a schematic perspective view of a surface coveringincorporating photovoltaic cells; and

FIG. 9 a shows a further schematic view of a covering elementincorporating a photovoltaic cell.

Referring first to FIG. 1 a, there may be seen end portions of first andsecond covering elements 2, 4 which may be joined to form a surfacecovering. Each covering element 2, 4 is formed as an elongate striphaving a length.

A first part of each covering element comprises a female member. Asecond part of each covering member comprises a male member forengagement with a female member. The first part has a top surface 6 anda basal surface 12, the basal surface 12 extending beyond the topsurface 6 to provide an open recess 10 for reception of a male member.The second part has a top surface 21 and a basal surface 23 and a malemember 22 protruding therebetween. The female member and the male memberproviding an interference fit upon engagement of adjacent coveringelements.

In more detail the female joint comprises a first overhanging member 7provided with an inclined or oblique surface 8, the open recessextending between the top surface 6 and the basal surface 12 beneath thetop surface and provided with a curved receiving surface 10 beneath theoverhanging member 7 and the basal surface terminating in an abutment inthe form of upstanding tooth 14. The top surface can be seen toterminate adjacent the open recess with the inclined or oblique surface8.

The male joint comprises a tongue having a first part 20 extending fromthe top surface 21 of the second covering element and a second partforming the male member 22 extending from a lower portion of the firstpart 20 such that a groove or notch 24 is formed between the second part22 of the tongue and the rest of the second covering element. A free endof the second part is provided with a shaped edge 26.

When the first and second parts engage the tongue 22 is received withinthe open recess 22, the shaped edge 26 matching with the curvedreceiving surface 10 to form an interference fit. This has an advantagethat the covering elements do not require the use of adhesive to besecured together to form the surface covering, thereby eliminating thisharmful and labour intensive task.

In addition, the abutment 14 is accommodated within the recess 24 uponengagement.

The covering elements may be manufactured from any suitable material.Such materials include flexible plastics materials.

Upon engagement of the male and female part a channel is formed in anupper part of the surface covering between the male and female parts.

In use, a sealing element or strip 30 of a suitable material, such as acaulking material, is located in the channel. The sealing strip may bemanufactured of any suitable material.

In FIG. 1 a the sealing strip 30 which the sealing strip is formed as aco-extrusion with the male part of the covering element. It is formed onthe male joint between an upper surface of the second part 22 of thetongue and the first part 20 of the tongue. The sealing strip 30 has anoblique or inclined surface 32 forming a gap or recess 34 between thesealing strip 30 and a part of the upper surface of the second part 22of the tongue.

The second element is conveniently joined to the second element in oneof two ways. Firstly, the mating edges of adjacent covering members arealigned such that the oblique surface 8 of the female joint is receivedin the gap or recess 34 of the male joint (e.g. in the direction ofarrow A). The covering elements 2,4 are then rotated with respect to oneanother such that the tooth 14 of the female joint engages the groove 24of the male joint.

In the case of flexible covering elements this insertion assembly methodmeans that additional covering elements can be added in confined spacesboth due to the flexible nature of the covering elements and that lesserclearance is needed than if the elements need to be horizontally alignedbefore joining.

On manufacture the tongue is sized to be an interference fit with thefemale joint. In the case of flexible elements, the tooth 14 is able todeflect around the tongue into the groove 24.

Alternatively, whether the covering elements are flexible or rigid, theends of adjacent covering elements may be aligned and the male joint fedlaterally into the female joint to form the surface covering (FIG. 1 b).Optionally a lubricant may be used to aid the sliding of the coveringelements.

A floor covering can be provided comprising forming a covering surfaceas described above and securing the covering surface to the floor. Acompressive or foam material can be attached to the underside of thecovering surface to provide further shock absorption.

Preferably the covering elements are joined to one another by sliding.Optionally a lubricant may be provided to aid such sliding

The sealing strip 30 in this arrangement has several advantages.

Firstly, when the surface covering is mounted onto a surface, where thesealing strip is extruded with the covering element and is oversize forthe channel formed on engagement, when the covering elements are broughttogether the sealing strip 30 is placed into compression causing adownward force to be exerted. This ensures the forming of a watertightseal between the adjacent covering elements. This also provides anopposing force to act against contraction of the covering elements overtime. The material of the sealing strip may be softer or harder than thematerial of the covering elements. If the sealing strip is harder thanthe covering elements, the covering elements are compressed by thesealing strip to provide the force to ensure that force is exerted toretain the covering elements together.

Further, while the joint is watertight it is not airtight, therebyallowing the under surface to ‘breathe’ as required. This has anadvantage when applying the surface covering to certain surfaces such aswood, due to the possibility of retained moisture which may otherwisecause lifting of the surface covering as the moisture expands due totemperature fluctuation.

Alternatively, a sealing strip 30 can be formed in situ in the channelformed on engagement of the covering members subsequent to engagement.The sealing strip can be added either as a liquid and allowed to set oradded as a preformed item. The sealing strip 30 may then be sanded orsubject to other treatment to obtain a desired surface finish. Thesealing strip 30 also provides for the formation of a surface seal.

In the case of flexible covering elements, the tightness of the jointsformed means that a covering surface can be manufactured without theneed for adhesive. This provides for a fast assembly. As a result of thetightness of the joint, the covering surface can be manufactured offsite, and may be conveniently stored for example by rolling up of thecovering surface.

The covering elements may be provided with a bonding sheet or equivalentto provide a bonding material to an underside of the covering element.The bonding sheet or equivalent may be double sided. As an alternativethe bonding sheet may be applied to the rear of an assembled surfacecovering. When supplied to an installer, the assembler simply removesthe back of the contact sheet and secures the covering element orsurface covering to the recipient surface using the exposed bondingmaterial.

The upper surface of the elements may be provided with tracks 50 (FIG. 8c) or other surface features to allow drainage of excess water. Thefeatures may be adjacent the joints between the covering elements.

Secondly, in use, covering elements formed of plastics material maycontract over time. The sealing strip 30 locating within the channel isable to accommodate such lateral contraction while maintaining aneffective seal.

To further protect against contraction of the covering elements, whetherlongitudinal, lateral or both, the covering elements may incorporatefibres, webbing or strands. These will also serve to restrict lateral orlongitudinal expansion due to temperature fluctuations.

Where the covering elements are flexible, the covering elements may bedistorted to form a curved covering surface. The lateral displacementbetween adjacent covering elements allows for the covering elements toform curved surface coverings. FIG. 1 c shows a section of surfacecovering displaced around a curve away from an assembled straight form(dotted lines). The arrows B show the relative movement of theindividual covering elements as the covering elements are curved.

FIGS. 2 and 3 show a further embodiment of the present invention. Likereference numerals are used throughout to refer to like parts. In FIG. 2the female joint is as the previous embodiment. The sealing strip 30 is,however, triangular in section and mounted to a sloping surface of theupper part 20 of the tongue. The adjacent covering elements form a jointas shown in FIG. 3 a.

FIG. 3 b shows the covering element 4 carrying the male joint beingflexed to enter the covering element 2 carrying the female joint. FIG. 3b also shows a further optional protrusion 40 on the lower part of themale joint that can be received within a suitable mating groove 42 on anouter edge of the upstanding tooth 14, the protrusion 40 being receivedwithin the groove 42 upon engagement.

It will be understood that suitable profiling of the male and femalejoints can facilitate bending of the covering elements during theassembly process. For example, grooves, slots 54 (FIG. 8 b) or hollowchannels 52 (FIG. 8 b) may be provided in the covering elements.

The hollow channels 52 may be used to convey gasses or liquids throughthe surface covering either to heat the surface or to cool the surfaceas required. Optimally a manifold may be provided at one end of thecovering element to facilitate passage of the medium, whether liquid orgas into the covering element.

In use, as noted, the lower surface of the covering elements 2,4 (and soof the surface covering formed by adjacent covering elements) may besecured to an underlying surface by adhesive. The underside may beprovided with profiling to allow for excess adhesive to be accommodatedas the surface covering is glued into position. The underside of theproduct can have a roughened, textured, embossed or laterally groovedcharacteristic with or without the described channelling, in order toprovide a good ‘key’ for gluing.

Where slots, such as the shaped slots 54 of FIG. 8 a are provided, thesemay also serve to accommodate excess adhesive 56 when the surfacecovering is being secured to a surface to be covered. The use of shapedslots can allow for the formation of a key 58 to aid further inanchoring the surface covering to the surface being covered.

Channels, sufficiently large grooving or other shaped slots 54 allow forexcess adhesive to travel laterally beneath the covering elementallowing for a more flat and even application of the surface covering toa surface.

The dimensions of the shaped slots 54 can be such that a cushioningeffect is achieved wherein air or soft material under the surface can becompressed under weight to cushion a fall or provide a more comfortablewalking feel making the overall surface covering suitable for gymnasiumsor around pools or child playing areas.

FIG. 4 shows a covering element 2 having a female joint to the righthand side and male joint to the left. The upper surface is provided withgrooves 58 of varying separation to produce a wood grain effect. Thegrooves 58 may be formed during the manufacture of the covering element,or subsequently, for example by embossing or other suitable technique.The underside of the covering element is provided with larger slots orrecesses 54 and with feet 55 between the recesses 54 themselves providedwith a surface texture 59, for example to aid in securing the surfacecovering to an underlying surface using an adhesive.

FIG. 5 shows a further embodiment of a surface covering joint inaccordance with the invention. The male and female joints have beenshaped such that a channel 57 is formed on the underside of the surfacecovering between the covering elements 2, 4. This channel allows for theaccommodation of excess adhesive in the manner described above. Alsoshown by the dashed line is the sealing strip 30 before compression.

FIG. 6 shows a further embodiment which in addition to the sealing strip30 provided at the upper surface of the joint, a second sealing strip 36is provided in a second channel formed at the lower surface of the jointupon engagement of the male and female part. It will be appreciated thatthe covering surface so formed is reversible. The upper and lowersurfaces can be provided with differing surface finishes or surfaceeffects so that alternatives may be provided for the respective surfacefinishes.

It will be understood that one of the finishes that may be provided to acovering element is a completely smooth, flat or untextured surface.

FIG. 7 shows a perspective view of a joint formed in accordance with theinvention. An upper surface of a first covering element 2 is shown byway of example having a textured finish 60. An upper surface of a secondcovering element 4 is provided with a variety of illustrative featuresincluding inclined channels 62 and grooves 64. These features areprovided to allow a reduced skin contact and to reduce the effect ofbare skin on a heated surface covering. The additional surface areacreated by these features also allows for greater heat dissipationincreasing this effect. These features are also selected to provideincreased grip, and allow for effective dispersion of excess water toprevent aquaplaning. Such features will also take time to wear down to asmooth effect.

As can be seen in relation to FIG. 7 the channels or grooves may beprovided laterally across the covering elements as an alternative tobeing provided extending longitudinally.

FIG. 9 shows how photovoltaic cells 70, or strips 72 of such cells canbe incorporated into a surface covering. Such cells (or strips) may beincorporated into the manufacturing process of the covering elements,for example included in the extrusion process, or appliedsubsequently—for example the covering elements may be provided with arecess or other retaining profile into which the cells (or a strip ofcells) can be positioned (as shown, for example, in FIG. 9 a). Thecovering elements can be provided with channels or other openings toaccommodate wiring for the cells (or strips). These grooves may be sizedto allow flexing of the covering element around a curve while retaininga photovoltaic cell within the covering element (FIG. 9A). The flexingof the retaining profile allows the appearance of curved photovoltaiccells (or strips). Additional elements may be included within thegrooves to hold the pholtovoltaic cells (or strips) in position.

The wiring for the photovoltaic cells (or strips) may be included withinthe covering element, running alongside the photovoltaic cells (orstrips) within a retaining profile (preferably along an inner retainingprofile when the covering element is curved) or in a gap formed betweenthe photovoltaic cells (or strips) and a recess formed in the coveringelement. The gap under the cells (or strips) can be adjustable.

As an alternative, the cells (or strips) can be incorporated into thesealing strip 30.

It will be understood that the surface covering need only contain asmany covering elements incorporating such photovoltaic cells (or strips)as are desired.

Alternatively the retaining profile may be use to retain a lightingelement as noted below or other element to provide a desired visualeffect.

In an alternative embodiment, the covering elements may be formed oftransparent material or incorporate transparent (or substantiallytransparent) portions. This allows for the surface covering toincorporate photovoltaic cells (or strips) within the covering elements,but beneath the upper surface of the covering elements, therebyprotecting the photovoltaic cells (or strips) from damage.

Alternatively, a surface covering incorporating such covering elementswith transparent regions could be overlaid onto an arrangementphotovoltaic cells (or strips).

Similarly, the covering elements may overlie a lighting arrangement toallow light through. Alternatively, the covering elements mayincorporate suitable lighting elements to allow for the bespoke formingof a lighting pattern or effect when the surface covering is assembledfrom the covering elements. The lighting elements may be formed with thecovering elements or retained in the manner described above for thephotovoltaic cells (or strips).

Magnetic elements may also be incorporated into the covering elements.For example, bar or strip magnets may be incorporated into the lowersurface of one or more covering elements making up a surface covering.Such a surface covering has particular application for covering steelsurfaces as it allows the surface covering to be secured in place, toprovide a suitable exposed surface having the desired properties, yetmay readily be lifted for inspection of the steel surface.

It will also be appreciated that, where appropriate, the coveringelements may incorporate stiffening elements. These may be incorporatedduring manufacture of the covering elements or more preferably, retainedin suitable receiving grooves in the covering elements as required toprovide the desired strengthening for a particular surface covering.

What is claimed is:
 1. A surface covering comprising two or morecovering elements, each covering element having A first part comprisinga female member; A second part comprising a male member for engagementwith a female member, The first part having a top surface and a basalsurface, the basal surface extending beyond the top surface to providean open recess for reception of the male member, The second part havinga top surface and a basal surface and a male member protrudingtherebetween, the female member and the male member providing aninterference fit upon engagement.
 2. A surface covering according toclaim 1 in which the open recess extends between the top surface and thebasal surface beneath the top surface to receive the male member beneaththe top surface.
 3. A surface covering according to claim 1, in whichthe top surface terminates adjacent the open recess in an inclinedsurface.
 4. A surface covering according to claim 1 in which the firstpart is further provided with an abutment and the second part isprovided with a recess, the abutment being accommodated within therecess upon engagement.
 5. A surface covering according to claim 4, inwhich one of the abutment and recess is provided with a protrusion, theother of the abutment and recess is provided with a groove, theprotrusion being received within the groove upon engagement.
 6. Asurface covering according to claim 1, in which upon engagement of themale and female part a channel is formed in an upper part of thecovering between the male and female parts.
 7. A surface coveringaccording to claim 6, in which a sealing element is located in thechannel.
 8. A surface covering according to claim 7, in which uponengagement the sealing element is under compression.
 9. A surfacecovering according to claim 7, in which the sealing element is formed asa co-extrusion with the female or male part of each covering element.10. A surface covering according to claim 9 in which the sealing elementis located on the male part above the male member.
 11. A surfacecovering according to claim 7, in which the sealing element is locatedin the channel subsequent to engagement.
 12. A surface coveringaccording to claim 1, in which the upper surface of at least onecovering element is provided with one or more of a roughened surface,channels or grooves.
 13. A surface covering according to claim 1, inwhich the lower surface of at least one covering element is providedwith one or more of a roughened surface, channels or grooves.
 14. Asurface covering according to claim 1, in which each covering element isprovided with ducts or channels extending along a length of the coveringelement.
 15. A surface covering according to claim 1, in which at leastone covering element is provided with at least one photovoltaic cell.16. A surface covering according to claim 14, in which the at least onephotovoltaic cell is retained in an upper surface of the coveringelement, or in which the photovoltaic cell is retained beneath atransparent or substantially transparent part of the covering element.17. A surface covering according to claim 1, in which at least onecovering element is provided with at least one lighting element.
 18. Asurface covering according to claim 1, in which at least one coveringelement is provided with one or more magnetic elements.
 19. A surfacecovering according to claim 1, in which at least one covering element isprovided with one or more stiffening elements.
 20. A surface coveringaccording to claim 1, in which the basal surface is provided withapertures extending therethrough.
 21. A joint having a first partcomprising a female member; a second part comprising a male member forengagement with a female member, the first part having a top surface anda basal surface, the basal surface extending beyond the top surface toprovide an open recess for reception of the male member. the second parthaving a top surface and a basal surface and a male member protrudingtherebetween, the female member and the male member providing aninterference fit upon engagement.